<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>4-async与await发送ajax</title>
</head>
<body>
    <button id="btn">点我发送ajax</button>

    <script>
        function sendAJAX(url){
            return new Promise((resolve,reject)=>{
                const xhr = new XMLHttpRequest();
                xhr.open("get",url);
                xhr.send();
                xhr.onreadystatechange = function(){
                    if(xhr.readyState === 4){
                        if(xhr.status >= 200 && xhr.status<300){
                            resolve(xhr.response);
                        }else{
                            reject(xhr.status);
                        }
                    }
                }
            })
        }

        let btn = document.querySelector("#btn");
        btn.addEventListener("click",async function(){
            let duanzi = await sendAJAX("https://api.apiopen.top/getJoke");

            console.log(duanzi);
        })
    </script>
</body>
</html>